Something occurred to me while listening to nikvoodoo talk about Burt's safe on We're Not Dead.
Locked and Loaded is a gun store and Burt's safe was obviously meant to house guns in it. So it does makes logical sense that it wouldn't be a 2X2X2 wall safe but rather a gun safe.

Like this one maybe. It would at least need to be large enough to hold several rifles, handguns, ammo, etc...